Removing Old Tiles and Ditra Matting

[Red]

Hi,

I have removed the old Tiles from my bathroom floor and underneath is Ditra matting of which I have also taken up.
The Ditra Matting has been put down with tile adhesive and what looks like either a 3 or 6mm trowel.
As I have pulled up the Ditra it has mostly left some of the felt backing behind and almost all of the adhesive.

What is the best way to proceed? Having to remove the old tile adhesive will not be easy as it looks as though it has gone directly onto the floor boards. Can I screw hardi backer boards over the top of whats been left? Or does it all need to be removed? Maybe there is a better solution I havnt thought of.

The floor will have underfloor heating and Tiles to go down on top of whatever I do next.

Any Advice greatly appreciated

Thanks

[All The Gear]

You'll probably have to remove the floorboards and replace with 18mm ply as if you are going to have an electric underfloor heating mat that is going to need to be laid onto insulation mats, minimum 10mm thick. You must use insulated mats or else you will be heating the downstairs ceiling instead of your bathroom floor.